Are chicken tractors predator proof?

Hi
I live in a rural community and by an open field. I am worried that a chicken tractor wouldn't be predator proof. I know there are skunks, mink, weasels, racoons and other animals in the area. Couldn't they get into the run at night or even the day? I would rather have a permanent coop and run but my husband doesn't want to run an electrical cord out to the coop in winter to heat up the water. During warm weather, I have a perfect location about 30 yards from the house. During winter we would keep it next to the garage and only have to run the electrical cord a short way. This would also offer more protection from the the winter winds.
Two questions:
1- How safe for the chickens are tractors?
2- Has anyone figured out a way to keep water from freezing in sub-zero weather without running power from the house?

I have been asking myself that question too. Chicken runs should have 12" of buried hardware cloth around their perimeter to deter predators. This is obviously impossible for a chicken tractor. I can see setting a few heavy blocks on the frame to weigh it down, obviously with the blocks being removed while moving the tractor.

Since posting I have read about wire aprons that can attach to a tractor. This seems like it would really help keep out the predators, but make it more awkward to move. I think I will do the permanent run.

I have been asking myself that question too. Chicken runs should have 12" of buried hardware cloth around their perimeter to deter predators. This is obviously impossible for a chicken tractor. I can see setting a few heavy blocks on the frame to weigh it down, obviously with the blocks being removed while moving the tractor.

I'm wondering the same thing. Could you put a wire floor on it that has holes big enough for the chickens to access the ground, but too small for a critter to get through? Just throwing out ideas. No personal experience, except with my birds getting taken by raccoons I'd like to avoid that this time.